Variable oscillator for code practice (CB7317E)

This circuit is from Popular Electronics from the 90s. The integrated circuit is not very common nowadays.

Headlight switch (CB7259E)
Found in a Popular Electronics from the 80's, this circuit makes use of a time integrated to...
Noise generator (CB23830E)
This random noise or white noise generator was published in Radio Electronics magazine in July...
LED Antiphase PWM Control (CB17289E)
With this circuit it is possible to control two LEDs of different colors, making their color...